Our moon is not the biggest moon in the solar system — not by a long shot. In fact, the Moon is only the fifth biggest satellite in our solar system, wedged right between Io and Europa in size ...

The size of the solar system is defined by the volume of space over which the sun’s influence exceeds those of other nearby stars in the Milky Way galaxy.

Pluto is 100 miles smaller than the smallest planet but is not a major planet. Here's which planet in our solar system takes the title instead.

A new virtual reality app lets users explore the solar system up close, from scorching-hot Mercury to faraway Pluto and beyond. The app, called Star Chart for VR, is billed as the first virtual ...